U.S. patent application number 16/652305 was filed with the patent office on 2020-07-30 for use of a new material in wind turbine parts and apparatus and methods thereof.
The applicant listed for this patent is Ventus Engineering GmbH. Invention is credited to Poul Anker Skaarup LUBKER, Shavkat MINGALIEV.
Application Number | 20200240391 16/652305 |
Document ID | 20200240391 / US20200240391 |
Family ID | 1000004798132 |
Filed Date | 2020-07-30 |
Patent Application | download [pdf] |
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United States Patent
Application |
20200240391 |
Kind Code |
A1 |
LUBKER; Poul Anker Skaarup ;
et al. |
July 30, 2020 |
USE OF A NEW MATERIAL IN WIND TURBINE PARTS AND APPARATUS AND
METHODS THEREOF
Abstract
The present invention relates to a wind turbine blade with a
blade structure comprising a surface and a load-carrying spar
supporting a shell structure, wherein the blade structure comprises
functionalized graphene-containing material. The present invention
relates to a wind turbine concrete tower comprising a load-carrying
structure extending vertically to a height, comprising
functionalized graphene-containing material. The invention further
relates to use of functionalized graphene-containing material in
wind turbine parts. The invention further relates to a method for
retrofitting a blade structure and the use of functionalized
graphene-containing material in a repair system for wind turbine
tower foundations. Furthermore the invention relates to use of at
least one sensor containing graphene.
Inventors: |
LUBKER; Poul Anker Skaarup;
(Baar, CH) ; MINGALIEV; Shavkat; (Vienna,
AT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ventus Engineering GmbH |
Vienna |
|
AT |
|
|
Family ID: |
1000004798132 |
Appl. No.: |
16/652305 |
Filed: |
October 2, 2018 |
PCT Filed: |
October 2, 2018 |
PCT NO: |
PCT/EP2018/076808 |
371 Date: |
March 30, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B32B 27/32 20130101;
F03D 13/20 20160501; B32B 2255/10 20130101; F03D 80/50 20160501;
B32B 2255/20 20130101; E04H 12/12 20130101; B32B 27/40 20130101;
B32B 2603/00 20130101; F03D 1/0675 20130101 |
International
Class: |
F03D 1/06 20060101
F03D001/06; F03D 13/20 20060101 F03D013/20; F03D 80/50 20060101
F03D080/50; E04H 12/12 20060101 E04H012/12; B32B 27/40 20060101
B32B027/40; B32B 27/32 20060101 B32B027/32 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 2, 2017 |
EP |
17194393.9 |
Claims
1. A wind turbine blade with a blade structure comprising: a
surface including a functionalized graphene-containing material
configured and arranged to provide a functional surface area; and a
load-carrying spar configured and arranged to support a shell
structure.
2. The wind turbine blade structure according to claim 1, wherein
the surface further includes a multi-layered structure with at
least one functional layer containing functionalized
graphene-containing material, said multi-layered structure
configured and arranged to also provide the functional surface
area.
3. The wind turbine blade structure according to claim 2, wherein
the multi-layered structure is a sandwich structure including
multiple functional layers, with at least one of the multiple
functional layer configured and arranged to function different from
another one of the other multiple functional layers.
4. The wind turbine blade structure according to claim 2, wherein
the multi-layered structure includes a top layer consisting of a
resin and having a thickness in a cured state in the range of
100-1000 .mu.m, and a bottom layer consisting of a resin and has a
thickness in a cured state in the range of 200-500 .mu.m.
5. The wind turbine blade structure of claim 2, wherein the
multi-layered structure includes a top layer made of thermoplastic
polyurethane, a bottom layer made of polyethylene, and at least two
intermediate layers being functional layers arranged between the
top and bottom layers.
6. The wind turbine blade structure of claim 2, wherein the surface
further includes two or more multi-layered structures, said
multi-layered structures are each configured and arranged to
provide a functional surface area, and wherein at least one of the
multiple functional surface areas is configured and arranged to
have one function different from another one of the other multiple
functional surface areas.
7. The wind turbine blade structure of claim 1, wherein the the
functionalized graphene-containing material of the surface is
hydrophobic.
8. The wind turbine blade structure of claim 1, wherein the
functionalized graphene-containing material of the surface consists
of one or more of the following: a resin, a coating, foam, paint,
liquid, ink, tape, combinations thereof, or a matrix comprising one
or more thereof.
9. A method of manufacturing a wind turbine blade including the
steps of: applying a surface coating on the wind turbine blade
including a functionalized graphene-containing material.
10. A method of retrofitting a wind turbine blade structure
including the steps of: applying a functionalized
graphene-containing material to a surface area of the wind turbine
blade.
11. The method of claim 10, wherein the step of applying a
functionalized graphene-containing material to the surface area of
the wind turbine blade includes applying a tape with a
multi-layered structure including at least one functional layer
containing the functionalized graphene-containing material.
12. A rotor of a wind turbine comprising: at least one sensor
containing graphene, said sensor being configured and arranged to
measure mechanical movements.
13. A wind turbine concrete tower comprising: a load-carrying
structure extending vertically to a height, said wind turbine
concrete tower comprising functionalized graphene-containing
material.
14. The wind turbine concrete tower according to claim 13, wherein
the height is more than 80 meters.
15. The wind turbine concrete tower of claim 13, further including
a surface with a multi-layered structure configured with at least
one functional layer containing the functionalized
graphene-containing material, said multi-layered structure provides
a functional surface area.
16. (canceled)
17. (canceled)
18. (canceled)
19. The wind turbine blade structure of claim 4, wherein the top
layer of the multi-layered structure has a thickness in the cured
state in the range of 100-500 .mu.m, and the bottom layer of the
multi-layered structure has a thickness in the cured state in the
range of 50-300 .mu.m.
20. The wind turbine blade structure of claim 4, wherein the top
layer of the multi-layered structure has a thickness in the cured
state in the range of 200-400 .mu.m, and the bottom layer of the
multi-layered structure has a thickness in the cured state in the
range of 70-150 .mu.m.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a general concept for
improving wind turbine part by use of a new material.
BACKGROUND OF THE INVENTION
[0002] The development in wind turbines continues in the pursuit of
increased energy output and all components in the wind turbine are
subject for enhancements including the design of the wind turbine.
This pursuit for increased energy output also embraces location of
the wind turbines for achieved optimal wind conditions.
[0003] The change in design of wind turbines and increased use in
more hostile locations, especially offshore, creates new challenges
both in terms of aerodynamics, durability and maintenance of the
individual parts constituting the wind turbine and of the complete
wind turbine.
[0004] One major change is being driven by a desire for longer
turbine blades. The longer the blade, the more power a wind turbine
can produce. Today's blades are up to 80 m in length, but the next
generations are likely to reach well over 100 m.
[0005] Based on today's construction of wind turbine blades,
lengthening a blade hugely increases its mass. The mass may be
increased by almost a factor of three.
[0006] The size and mass of today's wind turbine blades are already
approaching the point where the gravity of the blades induces the
dominant load on the wind turbine compared to the load induced by
the aerodynamics.
[0007] Reducing weight of the wind turbine blades has therefore
become a top priority in blade design. A reduction in weight should
be achieved without reduction in energy output and durability of
the blades. This creates a huge challenge for those working in
materials development.
[0008] The environmental conditions surrounding the wind turbine
may affect the design of wind turbine blades. Especially the rise
in offshore wind turbines amongst others has commenced the
development in wind turbine blades. Offshore turbines experience an
average wind speed of around 14 m/s off the coast of the UK, much
higher than onshore. The exposure to UV radiation combined with
rain, the high humidity of the salty sea air, extreme wind
conditions and high-speed spinning blades of an offshore wind
turbine combine to form a highly erosive environment that far
surpasses anything experienced by an aircraft. This seriously
affects the durability of the wind turbine blades, towers and
foundations.
[0009] Today, the blade tips on existing wind turbines may already
move through the air with speeds of up to 400 km/hour.
[0010] Especially durability is a high priority property for
offshore wind turbines. The remote location of offshore wind
turbines brings costly repairs and maintenance of the wind
turbines. Finding a way to extend the lifetime of materials is
therefore a priority for the industry. Thus, some of the challenges
in the wind turbine industry relates to optimizing the materials
used for the individual part comprising the wind turbine in regard
to durability, optimized properties in regard to the forces and
environmental conditions acting on the single parts of the wind
turbine and efficient production of the parts.
[0011] A major change is being driven by a desire for efficiently
producing large, lightweight blades that can cope with the harsh
environmental conditions in which they are operated including
offshore conditions.
[0012] Another major change is being driven by a desire for
increased hub height on wind turbines especially for on-shore
locations. Increasing the hub height hugely increases the output
from the wind turbine--each meter gained in hub height is said to
increase the yearly energy yield by 0.5-1%. Today's on-shore hub
height is up to 150 meter, but the next generations of on shore
wind turbines are likely to reach well over 200 m. Increasing the
hub height of the wind turbine has therefore also become a top
priority in tower design. An increase in hub height should be
achieved while improving strength of the tower with reduced weight
per height meter significantly and improve the durability of the
towers. This creates a huge challenge for those working in
materials development.
[0013] In order to go beyond what is currently possible with
traditional composites, a steep change in blade, tower and
foundation design and the materials used may be needed.
[0014] However, not only new wind turbines are subject to continued
development. The development in service and maintenance of existing
wind turbines may also pose for a steep change in methods and
material therefore to achieve continued cost-effective
operation.
OBJECT OF THE INVENTION
[0015] It is an object of this invention to overcome one or more of
the aforementioned shortcoming of the prior art.
DESCRIPTION OF THE INVENTION
[0016] The aforementioned aspects may be achieved by a wind turbine
blade with a blade structure comprising a surface and a
load-carrying spar supporting a shell structure, wherein the blade
structure comprises functionalized graphene-containing
material.
[0017] The load-carrying spar may also be referred to as a spar,
spar web or main spar amongst others. It may be formed as a
cylindrical structure, on or more bars. This is simply a few
examples and the structure is by no means limited to this. The
structure may also be referred to as a loadbearing structure.
[0018] A wind turbine blade comprises a leading edge, a trailing
edge, a suction side and a pressure side and extends from root to
tip. The pressure side may also be referred to as the upwind side
and the suction side as the downwind side.
[0019] Graphene is a one-atom-thick layer of carbon atoms arranged
in a honeycomb (hexagons or chicken-wire) crystal lattice.
[0020] Graphene-based materials may be functionalized with
different side groups for different properties. The number of side
groups per carbon atoms may differ depending on the
functionalization and/or which properties to achieve.
Functionalized graphene-based materials may be in dry powder form,
liquid or ink--these being inexhaustible examples.
[0021] The functionalized graphene-based materials may have
superior properties such as for example large surface area,
mechanical stability, tuneable electrical and optical properties
making it advantageous for use in wind turbines. The properties
further includes that it is stronger than steel, has a thin two
dimensional structure, is high conductive, high malleable, is
stretchable with further properties of being transparent, flexible,
hydrophobic, light absorbing, radar-absorbent and impermeable.
[0022] Graphene-based materials may be structured, designed or
presented in a number of ways: Porous wherein a number of carbon
atoms are lacking in the structure, it may be stacked or folded to
form 3D structures, the lateral size may be varied.
[0023] Graphene-based materials and functionalized graphene-based
materials may respectively be referred to as source graphene-based
materials and functionalized source graphene-based materials.
[0024] A method for functionalization of the graphene-based
materials may comprise the following acts: [0025] choice of
graphene-based materials, [0026] selection of appropriate chemical
side-group(s), and [0027] level and/or density of
functionalization.
[0028] This being an inexhaustible example.
[0029] Functionalized graphene-containing material may encompass
one or more functionalized graphene-containing material(s).
[0030] Functionalized graphene-based materials are extremely
diverse materials, and may be embedded in a matrix additive
host/carrier material to be used in material compositions matrix of
intermediate or host/carrier materials to produce different
materials with various significantly improved properties turning
the mix into a high-performance functionalized graphene-containing
material. The host/carrier material may have more than one
functionalized graphene-containing material added, depending on
which one or more properties are required to be synthesized into
the functionalized graphene-containing material.
[0031] The ratio for functionalized graphene-based materials
comprised in the functionalized graphene-containing material
depends on the host/carrier material and the properties to be
achieve for the functionalized graphene-containing material.
[0032] Correctly functionalized graphene-based materials have a
unique ability to give its attributes to the matrix of intermediate
or host/carrier materials. The functionalization may bring that the
graphene-based materials' rough texture expands thereby creating a
significant surface area. The planar structure of functionalized
graphene-based materials create a significant surface inducing a
large contact area with the host/carrier material because both the
top and bottom surfaces of a graphene sheet are in close contact
with the host/carrier material. The host/carrier material may be
the material in the matrix binding to the functionalized
graphene-based material.
[0033] In one aspect the graphene-based material may be
functionalized to bond tightly with surrounding polymers, improving
interfacial load transfers and boosts the surface area in contact
with the polymers.
[0034] Moreover, the aspect ratio (ratio between a lateral
dimension and the thickness of the graphene sheet) of a single
graphene sheet can reach more than 2000. The surface area of a
single graphene sheet can theoretically reach 2600 m2/g which may
provide a significant amount of potential sites for advantageous
chemical or physical interactions. This may accordingly improve
bonding between graphene sheet(s) and host/carrier material.
[0035] One effect of the embodiment comprising a blade structure
comprising a functionalized graphene-containing material may be
that the strength, stiffness and/or toughness of the blade may be
increased compared to using a non-graphene-containing material.
This may enable for longer, stiffer, lighter and/or more
damage-tolerant blades.
[0036] Non-graphene-containing material refers to a material not
comprising functionalized graphene-based materials.
[0037] Furthermore, due to the increased strength, stiffness and/or
toughness for a comparable blade comprising a functionalized
graphene-containing material compared to using a
non-graphene-containing material comprising material an improve
stability of the blades with a lower weight of the blades may be
achieved.
[0038] The increased strength, stiffness and/or toughness of the
blade may further be advantageous in regard to achieving a higher
energy yield per area of blade as the blade has a smaller risk of
being deflected by the wind forces acting on the blade.
[0039] This may be further advantageous in regard to extending the
length of the blades for higher energy yield per wind turbine or
per blade. Blade length is a bottleneck and one of the most import
factors in the development of rotor size and therefore a critical
factor for the entire wind turbine generator (WTG) development
today.
[0040] Furthermore the increased strength, stiffness and/or
toughness for a comparable blade using a functionalized
graphene-containing material compared to using a
non-graphene-containing material may be advantageous in regard to
that a reduced deflection/bending of the blade may achieve for
reduced fatigue and thus prolonged lifetime. Further advantages may
be mitigating the risk of cracks in the blades and/or in general
achieving more damage-tolerant blades. Mitigating the risk of
damages or increasing the damage-tolerance may generally result in
reduced service costs and extend lifetime.
[0041] In one aspect the two-dimensional structure of graphene
sheets may considerably reduce the cracks to emerge and/or develop
thereby reducing service costs and extend lifetime.
[0042] One effect of the embodiment comprising a blade structure
comprising a functionalized graphene-containing material may be
that the weight of the blade with a comparable strength, stiffness
and/or toughness of the blade to a blade using a
non-graphene-containing material may be reduced. This achieves for
new designs of the blades. New designs of the blades may include
features such as a changed weight distribution of the blade, new
blade profile as a few examples, however, by no means limited to
these examples. New blade profiles and changed weigh distribution
may be advantageous in regard to achieving a change in the
centrifugal forces acting on the wind turbine caused by the
rotation of the blades. It may be further advantageous in regard to
achieving increased aerodynamic efficiency of the blades.
[0043] The functionalized graphene-containing material may be
comprised in the load-carrying spar. The functionalized
graphene-containing material may be comprised in the shell
structure. The functionalized graphene-containing material may be
comprised in the blade structure to form part of the surface. The
functionalized graphene-containing material may be comprised in any
combination of the above parts.
[0044] Comprising functionalized graphene-containing material in
only a single part may have the effect that the weight of that part
of the blade may be reduce while maintaining or improving
properties for the entire blade such as strength, stiffness,
toughness and/or flexibility compared to a blade using a
non-graphene-containing material. This may be advantages in regard
to that a reduced deflection/bending of the part and/or the entire
blade may achieve for reduced fatigue and thus prolonged lifetime.
Further advantages may be mitigating the risk of cracks in the part
and/or the entire blade in general achieving more damage-tolerant
blades. Mitigating the risk of damages or increasing the
damage-tolerance may generally result in reduced service costs and
extend lifetime.
[0045] Comprising functionalized graphene-containing material in
any combination of parts may have the effect that the weight of one
or more parts may be reduced to achieve sufficient strength,
stiffness, toughness and/or flexibility of the entire blade
compared to a blade using a non-graphene-containing material part
of the blade. This may have the above mentioned advantages of
reduced deflection/bending and/or mitigated risk of cracks in the
one part, multiple parts or the entire blade. This may be
additional effects and advantages compared to those already
described.
[0046] In general, this may achieve for new designs of the blades,
as the change in one or more parts of the blade may affect changes
in other parts of the blade for achieving the aimed properties of
the entire blade.
[0047] The shell structure may comprise multiple shell parts. These
parts may comprise their own individual matrix of materials.
[0048] The functionalized graphene-containing material may be
comprised in the load-carrying spar, in the entire shell structure,
in a single shell part, or any combination thereof.
[0049] The percentage and type of functionalized graphene-based
material comprised in the one or more of the parts may differ for
each part depending on the properties to be achieved to that part
and/or depending on the matrix of materials for that part.
[0050] The percentage and type of functionalized graphene-based
material comprised in a dedicated area or volume in each part may
also differ depending on the properties to be achieved to that
location and part depending on the matrix of materials for that
location/part.
[0051] These above-mentioned variations may be further advantageous
in regard to a great freedom for designing the wind turbine blade
thereby achieving wind turbine blades with specific properties in
designated areas of the blade, with an advantageous weight
distribution and optimized blade profile.
[0052] The leading edge of a wind turbine blade is the region of
the blade that typically experiences the highest level of erosion,
as this is the edge that cuts through the air. The shell structure
and/or the surface may thus be constructed with properties aiming
at mitigating the occurrence and or development of erosion in this
part for prolonged lifetime of the wind turbine blade.
[0053] In one embodiment of the wind turbine blade a conductive
structure extends from a dedicated blade area to a blade root of
the wind turbine blade, wherein at least part of the conductive
structure is formed by the blade structure.
[0054] The conductive structure may be partly or fully formed by
the blade structure because the functionalized graphene-containing
material comprised in the blade structure may provide a conductive
material thereby forming a conductive structure.
[0055] The conductive structure may comprise additional conductive
structures forming further connections where the blade structure
only forms part of the conductive structure.
[0056] In one aspect the conductive structure is partly formed by
the surface.
[0057] In one aspect, the dedicated blade area may be the blade
tip.
[0058] In one aspect the additional conductive structures may be
formed by the load-carrying spar.
[0059] In case the conductive structure is fully formed by the
blade structure the embodiment may have the effect that a complete
conductor system can be achieved without incorporating further
structures to the wind turbine blade. This may provide for a
conductor system which is protected for reduced wear and tear.
[0060] One effect of this embodiment may be to incorporate a
lightning conductor system by use of functionalized
graphene-containing material in the blade structure. This may be
advantageous in regard to achieving new ways to design lightening
protection systems.
[0061] A further effect of the embodiment may be that the conductor
system may be designed with an increased lightening conductivity by
increasing the percentage of functionalized graphene-based material
or the type of functionalized graphene-based material in the
functionalized graphene-containing material in the shell structure,
in specific areas of the shell structure or even in the
load-carrying spar. This may have the advantage of achieving more
efficient and/or safer lightning conductor system
[0062] The lightning conductor system may achieve improved
lightning strike prevention, improved resistance to lightning,
ability to act as lightning rods to divert lightning away from
vulnerable areas amongst other benefits.
[0063] One effect of this embodiment may be to incorporate an
electro-static conductor system by use of functionalized
graphene-containing material in the blade structure.
[0064] This may be advantageous in regard to achieving new ways to
design electro-static conductor systems.
[0065] A further effect of the embodiment may be that the conductor
system may be designed with improved electro-static properties by
increasing the percentage of functionalized graphene-based material
or the type of functionalized graphene-based material in the
functionalized graphene-containing material in specific areas of
the blade structure. This may provide for improved electro-static
ability to act as anti-static roots to discharge and divert
anti-static away from vulnerable areas.
[0066] In one aspect the electricity conducting structure formed by
the blade structure may be used for heating purposes for de-icing
purposes. Functionalized graphene containing material may have both
a high electrical and heat conducting capacity making it suitable
for de-icing systems.
[0067] In one aspect the conductive structure is connected to a
controlled power source which is powered on/off according to
defined climatic conditions. One effect of this embodiment may be
achieving de-icing system which may be activated when there is
icing on the blades. Another effect may be achieving a de-icing
system which may be activated under certain climatic conditions to
prevent icing to accumulate on the blades.
[0068] This may be advantageous in regard to achieving a low energy
consuming de-icing system for wind turbine blades, where the
passage of an electric current through a conductor produces heat,
also known as Joule heating, Ohmic heating or resistive
heating.
[0069] A further advantage may be that no or considerably less
operational time with reduction of power curve due to icing on the
blades is achieved.
[0070] Yet a further advantage may be that no or considerably less
safety risk due to ice being thrown of the blades is achieved.
[0071] Yet a further advantage may be that no or considerably less
non-operational time where the wind turbines are shut down due to
icing on the blades is achieved.
[0072] Ice presents a major problem for wind turbine blades in cold
climates. There is great potential for wind energy in those
environments due to the favourable conditions. Available wind power
in cold climates is approximately 10% higher than in other areas
due to the increased air density at lower temperatures, and
according to recent estimates, 45 to 50 GW of power will be
installed in low-temperature regions by 2017.
[0073] In a further embodiment of the wind turbine blade the blade
structure comprises a surface which comprises functionalized
graphene-containing material providing a functional surface
area.
[0074] In one aspect the functional surface area may be light
absorbing.
[0075] In one aspect the functional surface area may be
radar-absorbent.
[0076] In one aspect the functional surface area may be heat- or
electrical conductive.
[0077] In one aspect the functional surface area provide may be
wear resistant, thereby meaning having an improved wear resistance
compared to a surface area, where non-graphene-containing material
is used.
[0078] In one aspect the functional surface area may be
hydrophobic.
[0079] In one aspect the functional surface may have a flush
surface.
[0080] In one aspect the functional surface may be structured.
[0081] Controlling the surface roughness may enable higher
aerodynamic efficiency of the blades, which may be translated into
a higher energy production from the wind turbine generator.
[0082] Hence, the surface may comprise multiple functionalized
graphene-containing materials. These may be arranged in a
multi-layered structure providing a functional surface area.
[0083] In one aspect the multi-layered structure may be a
prefabricated structure which is applied as part of the blade
structure and thereby forms part of the surface.
[0084] In one embodiment of the wind turbine blade the surface
comprises a multi-layered structure configured with at least one
functional layer containing functionalized graphene-containing
material, said multi-layered structure provides a functional
surface area.
[0085] One effect of the embodiment may be that the layered
structure may provide a surface functionality not present in the
top layer in itself. The surface functionality may be caused from
another layer in the structure. This may have the advantage of
obtaining a top layer acting for example as a protective layer for
another layer in the layered structure.
[0086] In one aspect the top layer may be the functional layer
containing functionalized graphene-containing material.
[0087] In another aspect a functional layer containing
functionalized graphene-containing material, may be a different
layer that the top layer.
[0088] In one embodiment of the wind turbine blade comprising a
multi-layered structure as part of the surface, the multi-layered
structure may be a sandwich structure comprising multiple
functional layers, with at least one functional layer having a
functionality being different from the functionality of another
functional layer.
[0089] One effect of this embodiment may be that a multifunctional
surface may be achieved. Such a multifunctional surface may be
impossible to achieve using a single functional layer, because the
graphene structures giving the different layer functionalities may
not be compatible together in the same matrix material.
[0090] Multiple layer functionalities may per nature of the layer
functionality not be incorporated in one layer. One exemplary
embodiment could be a functional layer being stretchable and
another layer having high mechanical stability which could be
relevant for use on a substrate with a high thermal expansion
coefficient.
[0091] Another effect may be that one of the layer functionalities
are enhanced by incorporating an additional functional layer with a
different layer functionality. One exemplary embodiment could be a
functional top layer with a high wearability or high environmental
resistance in combination with a functional intermediate layer
which is resilient or shock-absorbing. This combination may result
in an enhanced wearability or environmental resistance of the outer
surface due to decreasing the influence of impacting forces on the
outer surface.
[0092] In one embodiment of the wind turbine blade comprising a
multi-layered structure as part of the surface, the top layer may
be made of a resin. In a cured state the top layer may have a
thickness in the range of 100-1000 .mu.m (1E-6 m), preferably in
the range of 100-500 .mu.m or even more preferably in the range of
200-400 .mu.m. The multi-layered structure may comprise a bottom
layer made of a resin. In a cured state the additional layer may
have a thickness in the range of 200-500 .mu.m, preferably in the
range of 50-300 .mu.m or even more preferably in the range of
70-150 .mu.m.
[0093] The thickness of the single layers may be chosen according
to the application and the level of functionality. For example a
high-voltage application may be implemented using a layer with a
thickness in the millimetre to centimetre range.
[0094] In one aspect the layers may be made of polymers. The
functional layers may be polymer layers, where the functionalized
graphene-based materials are mixed into the resin.
[0095] In one exemplary embodiment of the wind turbine blade
comprising a multi-layered structure as part of the surface, the
multi-layered structure may comprise a top layer made of
thermoplastic polyurethane, a bottom layer made of polyethylene and
at least two intermediate layers arranged between the top layer and
the bottom layer.
[0096] In one aspect, the intermediate layers may be a functional
layer comprising a non-graphene-containing material. In one aspect,
the intermediate layers may be made of a non-graphene-containing
material. Hence, a material not comprising functionalized
graphene-based materials. In another aspect, the intermediate
layers may be a combination of the above. Intermediate layers made
of a non-graphene-containing material may contribute with further
functionalities to the surface area, hence, which do not originate
from any functionalized graphene-based materials.
[0097] In one aspect, the intermediate layer may comprise printed
and/or imprinted structures, which may be reproduced or partly
reproduced in the functional surface.
[0098] Another exemplary embodiment with an intermediate layer
having a functionality may comprise a resilient layer. A resilient
layer may be obtained without using a functionalized
graphene-containing material: in combination with a functional top
layer with a high wearability or high environmental resistance, an
enhanced wearability or environmental resistance of the outer
surface may be achieved.
[0099] Yet another exemplary embodiment may be a non-conductive
intermediate layer arranged between two conductive functional
layers. The non-conductive layer may have the effect of avoiding
shortcuts and/or other interaction between the two conductive
functional layers.
[0100] One advantage of using a non-graphene-containing material
may be possibility of using off-the-shelf materials which may
reduce costs for making the layered structure compared to using
functionalized graphene-containing material. Another advantage may
be easier and continuous availability of off-the-shelf materials
compared to functionalized graphene-containing materials.
[0101] In one exemplary embodiment the multi-layered structure may
comprise five layers, a top layer, a bottom layer and three
intermediate layers. The multi-layered structure may accommodate a
surface being super hydrophobic and particle repellant. The top
layer may be a transparent mat polymer film with a thickness in the
range 300 .mu.m. The intermediate layer adjacent to the top layer
may accommodate a functional layer being light-absorbing and thus,
with a reduced light reflectance back to the top layer. The
intermediate layer, adjacent to the light-absorbing layer, may be a
conductive functional layer accommodating for Joule heating to
support a de-icing functionality. The next intermediate layer,
being the layer between the conductive functional layer and the
bottom layer may accommodate a functional layer being an organic
solar cell or a photovoltaic. This layer may provide for power
delivery to the Joule heating and thus the de-icing functionality.
The bottom layer may have an adhesive effect.
[0102] In one exemplary embodiment the multi-layered structure may
comprise six layers, a top layer, a bottom layer and four
intermediate layers. The multi-layered structure may accommodate a
surface being super environmentally resistant. The top layer may be
a transparent elastic mat polymer film with a thickness in the
range of 300 .mu.m. The intermediate layer adjacent to the top
layer may be flexible and impact-absorbing. This may be provided by
a 60 .mu.m transparent acrylic PSA film. However, other polymer
films may also be used. The impact-absorbing layer may cause the
functional surface area to provide for a functional surface area
being super environmentally resistant. This may be due to dampening
the impacts of particles inflicting on the surface area. The
remaining four layers of the layered structure--the three remaining
intermediate layers and the bottom layer--may be a structure
similar to that described for the multi-layered structure, possibly
accommodating a surface being super hydrophobic and particle
repellant, with a functional layer being light-absorbing, a
conductive functional layer accommodating for Joule heating to
support a de-icing functionality, a functional layer being an
organic solar cell or a photovoltaics layer, and the bottom layer
may have an adhesive effect.
[0103] In one embodiment a wind turbine blade surface may comprise
two or more multi-layered structures. The multi-layered structures
may each provide a functional surface area. At least one functional
surface area may have a functionality being different from the
functionality of another functional surface area.
[0104] One effect of this embodiment may be that the surface may be
provided with multiple functional surface areas being different
from each other, thereby optimizing the blades according to their
use and location. Especially the leading edge of a wind turbine
blade experiences a high level of erosion, as this is the edge that
cuts through the air.
[0105] In one exemplary embodiment the six-layered and five-layered
structures described above may be applied to a wind turbine blade.
The six-layered structure may be applied to the leading edge
accommodating for a surface being super environmentally resistant.
In combination with that the five-layered structure may be applied
to remaining areas of the wind turbine blade, accommodating for a
surface being super hydrophobic and particle repellant, this means
that a surface may be achieved with multiple functional surface
areas having different functionalities according to the use.
[0106] In a further embodiment of the wind turbine blade the blade
structure comprises a surface which comprises functionalized
graphene-containing material providing a hydrophobic surface.
[0107] One effect of this embodiment may be to mitigating building
up a surface adhering water layer on the blade surface This may be
advantageous in regard to preventing excess weight on the blade
from a thin layer of water thereby preventing a reduction in the
power curve of the wind turbine.
[0108] A similar effect of this embodiment may be to mitigate the
build-up of ice on the surface of the blade thereby achieving no or
considerably less need for de-icing of the blade. A further
advantage may be no or considerably less operational time with
reduction of power curve due to icing on the blades. Yet a further
advantage may be no or considerably less safety risk due to ice
being thrown of the blades. Yet a further advantage may be no or
considerably less Non-operational time where the wind turbines are
shut down due to icing on the blades.
[0109] In a further embodiment of the wind turbine blade the shell
structure, or part of the shell structure, comprises a surface
coating which comprises a functionalized graphene-containing
material providing a light absorbing surface.
[0110] One effect of this embodiment may be to considerably reduce
or completely eliminate light reflections from the blade on a wind
turbine during the rotation of the blades, which is a major issue
of concern for on-shore turbines located in inhabited areas.
[0111] A may have the advantage that no or considerably less visual
pollution from wind turbines may be achieved. This is especially
advantageous in regard to achieving new locations for on-shore wind
turbines closer to inhabited areas.
[0112] A further advantage may be no or considerably less
non-operational time is achieved where the wind turbines are shut
down due to light reflections from the blades.
[0113] In a further embodiment of the wind turbine blade the shell
structure, or part of the shell structure, comprises a surface
coating which comprises a functionalized graphene-containing
material providing a radar-absorbent surface.
[0114] One effect of this embodiment may be to considerably reduce
or completely eliminate radar reflections from the blade on a wind
turbine during the rotation of the blades to make them less visible
(ideally invisible) to radar, which is a major issue of concern for
wind turbines located close to airports and other sensitive areas.
One of the main problems related to wind turbine blades is that
they are extremely reflective to radar energy. This energy can
cause problems not only for the radar, but also for the radar
operators watching the display.
[0115] It may have the advantage that no or considerably less radar
pollution from wind turbines may be achieved. The existing and new
wind turbine blades surface can be modified so that it is less
visible to the radar and hence causes fewer radar display plots.
This is especially advantageous in regard to achieving new
locations for wind turbines closer to airports areas and other
sensitive areas.
[0116] A further advantage may be no or considerably less
non-operational time is achieved where the wind turbines are shut
down due to radar reflections from the blades.
[0117] In a further embodiment of the wind turbine blade the shell
structure comprises a surface, or part of the surface, which
comprises a functionalized graphene-containing material providing a
wear resistant surface.
[0118] One effect of this embodiment may be to improve the
anti-erosion and/or durability properties. This may have the
advantage to prevent or at least reduce erosion of the leading edge
of the blade also referred to as leading edge erosion.
[0119] Erosion of the leading blade edge may be a significant
problem on off shore wind farms and on onshore wind farms located
in sandy areas since the power curve is considerably reduced when
leading edge erosion changes the roughness of the surface and the
wind turbine have to be taken out of operation for maintenance.
[0120] The advantage of maintaining or improving a given smoothness
of the leading edge and/or the entire blade surface may generally
improve the power curve. A maintained or improved smoothness of at
least part of the blade may improve the power curve under certain
weather conditions. A maintained or improved smoothness of at least
part of the blade may reduce noise emission from the blades in
general and/or under certain weather conditions.
[0121] In one aspect, the functionalized graphene-containing
material comprised in the surface may provide for general improved
barrier properties of the surface such as a hydrophobic surface, a
wear resistant surface and/or an environmental resistant
surface.
[0122] One effect of this embodiment may be improved barrier
properties of the surface may be to prevent dirt, salt, and/or
insects amongst others from sticking to the surface. One advantage
may be to mitigate excess weight on the blade or imbalance from
different wear patterns on the surface and/or a layer of
contaminations.
[0123] Another advantage may be to prevent no or less reduction of
the power curve due to contaminations on the blade surface, thereby
increasing yearly production from the wind turbine.
[0124] Yet another advantage may be reduced cost for cleaning the
blades, thereby eliminating or reducing downtime for cleaning the
blades, thereby increasing yearly output from the wind turbine.
[0125] In one embodiment of the wind turbine blade functionalized
graphene-containing material may be chosen amongst: a resin, a
polymer, an epoxy, a coating, foam, paint, liquid, ink, tape,
combinations thereof, or a matrix comprising one or more
thereof.
[0126] Tape may comprise a foil, a film, a sheet or comparable
structures and thus be comparable to such structures. The tape may
comprise a multi-layered structure such as at least an adhesive
layer and a top layer. The tape may comprise additional layers in
between the adhesive layer and the top layer.
[0127] In one aspect parts of the multi-layered structure may be
extruded or produced by comparative processes or concepts.
[0128] In one aspect functionalized graphene-based material may be
mixed into a matrix of intermediary or host/carrier materials.
[0129] In one aspect the functionalized graphene-based material may
be in dry powder form including granulate or other dry forms.
[0130] In one aspect the functionalized graphene-based material may
be in liquid form.
[0131] In one aspect the functionalized graphene-based material may
be an ink.
[0132] As previously described, correctly functionalized
graphene-based material has a unique ability to give its attributes
to intermediary or host/carrier materials to which it bonds,
thereby achieving the effects and advantages previously described
for the wind turbine blade comprising a functionalized
graphene-containing material.
[0133] The functionalized graphene-containing material may be a
matrix of additive materials containing functionalized
graphene-based material which can be used in material compositions
to significantly improve mechanical and physical properties.
[0134] One effect of the embodiment may be that the functionalized
graphene-containing material may be materials at least suited for
wind turbine blades, thereby achieving that the design of the wind
turbine blades is not limited by one or two materials. Instead a
broad range of designs may be possible choosing the functionalized
graphene-containing material according to the properties to be
obtained.
[0135] An object of the invention may be achieved by use of
functionalized graphene-containing material in a shell structure of
a wind turbine blade.
[0136] An object of the invention may be achieved by use of
functionalized graphene-containing material in a load-carrying spar
of a wind turbine blade.
[0137] The shell structure and/or the load-carrying spar of a wind
turbine blade are often made using a combination of several
composite materials, making production significant complex, as each
material will behave differently at each temperature. Even with
careful control, you run the risk of exceeding the heat capability
of one or more of the materials, destroying the blade's structural
integrity before it even goes into use. The process by which the
polymer matrix component hardens, and/or the effectiveness of this
process, may have a huge impact on the strength of the final
composite. This may also affect the functionalized
graphene-containing material and the properties thereof. Use of
functionalized graphene-containing material may provide for better
terminal conductivity this may be advantageous in regard to
achieving optimized formation of chemical bonds in the
manufacturing process, and thus improved final performance of the
blades.
[0138] Use of functionalized graphene-containing material may also
provide for better electrical conductivity. This may be
advantageous in regard to achieving a low energy consuming heating
system, where the passage of an electric current through a
conductor produces heat, also known as Joule heating, Ohmic heating
or resistive heating. This may be advantageous in regard to
achieving optimized formation of chemical bonds in the
manufacturing process, and thus improved final performance of the
blades.
[0139] The effects and advantages of the use of a functionalized
graphene-containing material in the shell structure or in the
load-carrying spar may be in line with those previously described
and includes amongst others: [0140] Increased terminal
conductivity, which may be important in the manufacturing process
[0141] Providing an electrical conducive material [0142] Increased
lightning conducting properties [0143] Increased electro-static
properties [0144] Increased strength, stiffness and toughness
[0145] Improved impact resistance
[0146] Thereby achieving amongst others the following advantages:
[0147] Improved fire retardation [0148] Faster moulding time due to
faster temperature equilibrium. [0149] Less laminating time and
reduced process costs [0150] Increased resistance to delamination
[0151] Weight savings [0152] Reduced material costs [0153] Reduced
exothermic and micro cracking during fabrication [0154] Enabling
thicker section mouldings and manufacture of thicker structures
[0155] More homogeneous and better part quality [0156] Increased
damage tolerance [0157] May be used for de-icing purposes [0158]
Ability to act as lightning rods to divert lightning away from
vulnerable areas [0159] Ability to act as anti-electro-static rods
to discharge and divert electro-static away from vulnerable areas
[0160] Ability to act as a light absorbing surface [0161] Ability
to act as a Radar-absorbent surface.
[0162] An object of the invention may be achieved by use of
functionalized graphene-containing material in a surface coating of
a wind turbine blade.
[0163] In one aspect, the surface coating may be paint.
[0164] In one aspect the surface coating may be ink.
[0165] In one aspect the surface coating may be tape.
[0166] In one aspect the surface coating may be a blade coating
and/or a gel coat systems.
[0167] In one aspect, the surface coating may be in a liquid form
with a suitable viscosity hardening by itself or by introducing an
external hardening accelerator.
[0168] Hence, the surface may comprise multiple functionalized
graphene-containing materials. These may be arranged in a
multi-layered structure providing a functional surface area.
[0169] In one aspect the multi-layered structure may be a
prefabricated structure which is applied as part of the blade
structure and thereby forms part of the surface.
[0170] One effect of these uses may be that the shell structure may
be covered using different coating thickness or different
percentages of functionalized graphene-based material or different
types of functionalized graphene-based material in the
functionalized graphene-containing material used in specific areas
of the blade, thereby achieving individual properties for
individual areas.
[0171] Another effect may be that the shell structure may be
covered by applying different functionalized graphene-containing
material on different locations/areas of the blade depending on the
wanted functionality.
[0172] Use of a functionalized graphene-containing material may
also provide for better electrical conductivity. This may be
advantageous in regard to achieving a low energy consuming heating
system, where the passage of an electric current through a
conductor produces heat, also known as Joule heating, Ohmic heating
or resistive heating. This may be advantageous in regard to
achieving optimized fit to the blade shells and formation of
chemical bonds in a hardening process, and thus improved final
performance and longevity of the surface coating system.
[0173] The effects and advantages of the use of a functionalized
graphene-containing material in a surface coating may be in line
with those previously described in connection with the surface
properties of the invention.
[0174] An object of the invention may be achieved by a method for
retrofitting a blade structure of a wind turbine blade, the method
comprising an act of applying a functionalized graphene-containing
material to a surface area of the wind turbine blade.
[0175] In one aspect the functionalized graphene-containing
material may be a blade coating, a gel coat systems and/or a
liquid.
[0176] In further embodiments the use of functionalized
graphene-containing material may be combined by using it in any
combination of a shell structure, a load-carrying spar and/or a
surface coating or in all three parts.
[0177] The use of functionalized graphene-containing material in
multiple parts of a wind turbine blade may have the effect that the
weight of one or more parts may be reduced to achieve sufficient
strength, stiffness, toughness and/or flexibility of the entire
blade compared to a blade using a non-graphene-containing material
part of the blade. This may have the above mentioned advantages of
reduced deflection/bending and/or mitigated risk of cracks in the
one part, multiple parts or the entire blade.
[0178] This may be additional effects and advantages compared to
those already described for the individual use.
[0179] In general, this may achieve for new designs of the blades,
as the change in one or more parts of the blade may affect changes
in other parts of the blade for achieving the aimed properties of
the entire blade.
[0180] In one aspect the retrofitting may be a method applied for
new blades or existing blades.
[0181] In one aspect the retrofitting may include repair of
existing blades.
[0182] The functionalized graphene-containing material may be
applied by spraying functionalized graphene-containing material in
liquid form onto the blade surface or by applying a functionalized
graphene-containing material to the surface of the shell structure
or on top of the existing surface or parts hereof. One effect of
this embodiment may be that the shell structure may be retrofitted
using different coating thickness, different percentages of
functionalized graphene-based material in the functionalized
graphene-containing material, and/or different types of
functionalized graphene-based material in the functionalized
graphene-containing material used in specific areas of the blade
structure.
[0183] Another effect may be that the shell structure may be
retrofitted by applying the functionalized graphene-containing
material on different locations/areas of the blade depending on the
wanted functionality.
[0184] Use of a functionalized graphene-containing material may
also provide for better electrical conductivity. This may be
advantageous in regard to achieving a low energy consuming heating
system, where the passage of an electric current through a
conductor produces heat, also known as Joule heating, Ohmic heating
or resistive heating. This may be advantageous in regard to
achieving optimized fit and formation of chemical bonds in a
hardening process, and thus improved final performance of the
repair system.
[0185] The effects and advantages of the retrofitting may be in
line with those previously described in connection with the shell
structure properties and surface properties of the invention.
[0186] In a specific embodiment of the method for retrofitting a
blade structure of a wind turbine blade with the effects and
advantages in line with those just described, the method may
comprise an act of applying a tape with a multi-layered structure
configured with at least one functional layer containing
functionalized graphene-containing material.
[0187] This embodiment may have the effect of an off-the-self tape
providing different surface functionalities. Thus, different areas
of the wind turbine blade may be retrofitted with different surface
functionalities. Hence, the surface being modified for
surroundings, having different impacts on the surface.
[0188] Furthermore, the adhesive properties may be made suitable
for specific substrate faces in regard to the material types
comprised in the existing surface of the blades.
[0189] Additionally, this embodiment may have the effect that the
attachment of the layered structure may be performed without health
risks due to hazardous substances, e.g. aerosols being released or
created in the attachment process.
[0190] In the pursuit for increased energy output, the development
in wind turbines continues as mentioned includes all components in
the wind turbine to be subject for enhancements and the location of
the wind turbines.
[0191] Thus, a further advantage may be no or considerably less
visual pollution from existing wind turbines if surface coatings
comprising a functionalized graphene-containing material is
retrofitted to blades on existing wind turbines. The retrofitting
system where new gelcoat, tape, paint, liquid or ink may be added
on the existing surface or part of the existing surface.
[0192] A repair system or retrofitting system may comprise a
gelcoat, tape, paint, liquid or ink to be added on the leading edge
of the wind turbine blade which may lead to an improved surface
roughness or smoothness and a slower degrading surface. An improved
surface roughness or smoothness of at least part of the blade may
improve the power curve under certain weather conditions. An
improved surface roughness or smoothness of at least part of the
blade may also reduce noise emission from the blades in general
and/or under certain weather conditions.
[0193] A further object of the invention may be achieved by use of
at least one sensor containing graphene arranged in the rotor of a
wind turbine suitable for measuring mechanical movements.
[0194] A sensor containing graphene may comprise one or more
graphene-containing materials, and where the sensor's measuring
properties are achieved by using at least one graphene-comprising
material.
[0195] The rotor of the wind turbine comprises the wind turbine
blades. The rotor on a wind turbine harvest the energy from the
wind, and therefore the rotor is often in popular terms described
as the motor of a wind turbine.
[0196] The mechanical movements may include for low frequency
movements, vibrations, and/or acceleration in the rotor.
[0197] Due to the properties of functionalized graphene-based
materials and functionalized graphene-containing materials
previously described including amongst others a large surface area,
mechanical stability, highly conductive, tuneable electrical and
optical properties, thin two dimensional structures, being
stretchable. These properties may be used in a sensor containing
graphene for accuracy, sensitivity and sensing speed thereby being
useful for continuously monitoring of mechanical movements in
existing and future wind turbine blades and rotors.
[0198] By locating a sensor containing graphene in at least one of
the blades in the rotor of a wind turbine for measuring mechanical
movements, it may be achievable to monitor mechanical movements in
different parts of the rotor at a very high accuracy, with improved
sensitivity and with increased sensing speed compared to
non-graphene-containing material sensors. Thereby achieving to
identify unwanted mechanical movements or changes in mechanical
movements which may indicates faults in a rotor part which may be
advantageous in regard to achieving greater equipment reliability
and reduced risk.
[0199] It may also be achieved to monitoring the wind conditions
hitting the entire rotor swept area on the individual wind turbines
thereby achieving for diagnosing of for example blade damage, yaw
misalignment of the rotor plane, the actual mechanical function,
tolerances and adjustment of the blade pitch, pitch bearing
failures and the behavior and the aerodynamic efficiency of
individual rotor blades at any 360.degree. position and of the
entire rotor at any 360.degree. position, this being an
inexhaustible list.
[0200] A wind turbine rotor is made up of components integrated
into a finely balanced construction designed to last for 20 years
or more. Any damaged or faulty rotor blades can reduce overall
productivity and result in premature wear and tear on turbine
components and a significant drop in performance.
[0201] Therefore any unbalance in the rotor should be identified as
soon as possible and any damage repaired before it deteriorates and
becomes a serious problem leading to costly repairs, lost revenue
or even catastrophic failure.
[0202] The sensor may also be used to optimize the aerodynamic
efficiency of the individual blades and of the entire rotor and in
consequence hereof obtaining the best possible generator power
production and lowest loads to be within the specifications.
[0203] Wind farm operators and OEMs have been searching for a
condition monitoring system for blades and rotors on individual
wind turbines and on wind turbine fleets capable of detecting
adverse conditions and predicting failures, in order to help
minimize risks and prioritize preventive maintenance and repairs,
including strain gauges, acoustics, lasers and thermography--but
until now with limited success.
[0204] Therefore even though some parts of a wind turbine can be
monitored, such as the gearbox, generator and main bearing, there
is currently no real-time health overview and condition monitoring
of blades and rotors on individual wind turbines and on wind
turbine fleets beyond manual inspections, typically done once a
year.
[0205] These aspects may be further achieved by a wind turbine
concrete tower comprising a load-carrying structure extending
vertically to a height, comprising functionalized
graphene-containing material.
[0206] The term wind turbine concrete tower comprises wind turbine
towers wherein a concrete structure is comprised in the tower, and
which concrete structure has a function for the tower. This
function may be load-carrying, a supporting structure, strength
reinforcing structure, function as a surface shell or a surface
coating. These are only a few examples and the function of the
concrete structure is by no means limited to these.
[0207] The wind turbine concrete tower may--as a non-limiting
example--be a concrete hybrid tower with concrete base and middle
sections and steel top.
[0208] Functionalized graphene-containing material may encompass
one or more functionalized graphene-containing material(s).
[0209] Within the last 3-5 years different concrete tower systems
have been invented. Based on the experience of these systems, the
expectations in the market is, that--even though the number of
concrete towers today is low--there will be a rapid move from steel
to concrete towers which is expected to be the winning WTG tower
technology.
[0210] One effect of this embodiment may be improved strength of
the tower with reduced weight per height meter. This may be
advantageous in regard to achieving a reduction in the amount of
concrete and/or the amount of steel reinforcement required of a
tower of a given height and strength compared to previously
suggested concrete towers.
[0211] This may further be advantageous in regard to allowing for
adoption of higher, thinner and/or lighter concrete towers,
allowing for new designs, reduced steel reinforcement and concrete
consumption and improved environmental sustainability, including:
[0212] Enabling completely new concrete tower assembly systems and
methods compared to traditional concrete towers, which furthermore
may enable a completely new logistical puzzle, where the towers may
not be too heavy and/or wide to pass under bridges, through
tunnels, cross roads and bridges from production facility to the
wind turbine site, thereby further reducing logistic costs
considerably. [0213] Enabling new concrete tower assembly systems
and methods which may reduce the need for large cranes on
production site and/or wind turbine site, thereby further reducing
costs. [0214] Enabling new concrete tower assembly systems and/or
methods, which may offer considerably more strength to the towers
themselves, thereby allowing for the opportunity to use new
inventions of cranes "crawling" up and down on the tower structure
when erecting and servicing the wind turbines. This may further
reduce costs in the construction, servicing and/or maintenance
phase(s). [0215] Enabling concrete tower which may offer a welcome
opportunity to introduce towers which is even higher than
today.
[0216] A further effect of this embodiment may be improved
stiffness and thereby improved stability of the tower. This may
have the advantage of achieving extended lifetime of the tower.
Some indications points in the direction of an extended life time
of up to 60 years may be achieved compared to steel towers which
may have lifetimes in the range of 20 years and traditional
concrete towers which are considered to have lifetimes in the range
of 40 years.
[0217] A further advantage improved stiffness and thereby improved
stability of the tower may be mitigating unwanted movements and/or
vibrations in the tower during the wind turbine start-up phase, in
the operational phase and/or during the stop phase.
[0218] This may further be advantageous in regard to allowing for
adoption of thinner, lighter and/or higher concrete towers,
allowing for new designs, reduced concrete consumption and improved
environmental sustainability, including: [0219] Enabling a larger
footprint base of the tower which then requires a much simpler and
less costly foundation than for steel towers and also for
traditional concrete towers without functionalized
graphene-containing material.
[0220] A further effects of this embodiment may be increased
terminal conductivity in the functionalized graphene-containing
material and/or thereby the tower construction. This may be
advantageous in the manufacturing process thereby achieving
properties such as: [0221] Faster hardening time during fabrication
due to faster temperature equilibrium. [0222] Increased resistance
to delamination during fabrication [0223] Reduced exothermic and
micro cracking during fabrication [0224] Enabling thicker section
mouldings and manufacture of thicker structures [0225] More
homogeneous and better part quality [0226] Reduced process costs,
amongst others.
[0227] By reducing delamination, exothermic and micro cracking
during fabrication, the development of micro-sized cracks in the
load carrying concrete structure may be prevented or delayed
considerably because nano-sized cracks are controlled before they
develop into micro-sized cracks, which therefore further improve
resistance to tensile stresses.
[0228] A further effect of this embodiment may be that the
functionalized graphene-containing material provides for an
electrical conducive material constituting an entire or part of an
electrical conductive structure of the wind turbine concrete
tower.
[0229] In one aspect the conductive structure may comprise
additional conductive structures forming further connections where
the functionalized graphene-containing material only forms part of
the conductive structure.
[0230] In one aspect the conductive structure may be partly formed
by the surface. In one aspect, the functionalized
graphene-containing material may constitute a dedicated area on the
surface of the tower.
[0231] In one aspect, the functionalized graphene-containing
material may be of different coating thickness or different
percentages of functionalized graphene-based material or different
types of functionalized graphene-based material in the
functionalized graphene-containing material used in dedicated areas
of the tower structure.
[0232] In case the conductive structure is fully formed by the
functionalized graphene-containing material and/or the basic
elements used in the tower structure the embodiment may have the
effect that a complete conductor system is achieved without
incorporating further structures to the wind turbine concrete
tower. This may provide for a conductor system which is protected
for reduced wear and tear.
[0233] One effect of this embodiment may be to incorporate a
lightning conductor system by use of functionalized
graphene-containing material in the tower structure and/or the
tower surface.
[0234] This may be advantageous in regard to achieving new ways to
design lightening protection systems.
[0235] A further effect of the embodiment may be that the conductor
system may be designed with an increased lightening conductivity by
increasing the amount of functionalized graphene-based material in
the functionalized graphene-containing material in specific areas
of the tower structure. This may have the advantage of achieving
more efficient and/or safer lightning conductor system
[0236] The lightning conductor system may achieve improved
lightning strike prevention, improved resistance to lightning,
ability to act as lightning rods to divert lightning away from
blades, nacelle and/or other vulnerable areas.
[0237] One effect of this embodiment may be to incorporate an
electro-static conductor system by use of functionalized
graphene-containing material in the tower structure.
[0238] This embodiment may be further advantageous in regard to
achieving new ways to design electro-static conductor systems.
[0239] A further effect of the embodiment may be that the conductor
system may be designed with improved electro-static properties by
increasing the amount of functionalized graphene-based material in
the functionalized graphene-containing material in specific areas
of the tower structure. This may provide for improved
electro-static ability to act as anti-static rods to discharge and
divert anti-static away from blades, nacelle and/or other
vulnerable areas.
[0240] In one aspect the electricity conducting structure formed by
the tower structure may be used for heating purposes for de-icing
purposes. Functionalized graphene-containing material may have both
a high electrical and heat conducting capacity making it suitable
for de-icing systems.
[0241] In one aspect the conductive structure is connected to a
controlled power source which is powered on/off according to
defined climatic conditions. One effect of this embodiment may be
achieving de-icing system which may be activated when there is
icing on the tower. Another effect may be achieving a de-icing
system which may be activated under certain climatic conditions to
prevent icing to accumulate on the tower.
[0242] This may be advantageous in regard to achieving a low energy
consuming de-icing system for wind turbine towers, where the
passage of an electric current through a conductor produces heat,
also known as Joule heating, Ohmic heating or resistive
heating.
[0243] One further effect may be an increased toughness of the
concrete offering advanced properties leading to improved such as
fire retardation and/or a reduced level of maintenance leading to
maintenance free towers.
[0244] In one aspect the functionalized graphene-containing
material may provide for improved barrier properties of the surface
such as hydrophobic surface.
[0245] This may have the effect of preventing build-up of a surface
adhering water layer. This may lead to no or considerably less
build-up of ice on the surface of the tower, which may achieve for:
[0246] no or considerably less need for de-icing of tower [0247] no
or considerably less safety risk due to ice being thrown of the
tower [0248] no or considerably less non-operational time where the
wind turbines are shut down due to icing on the tower.
[0249] In one aspect the functionalized graphene-containing
material may provide for a conductive material.
[0250] Functionalized graphene-containing material may have both a
high electrical and heat conducting capacity. The effects and
advantages of these properties are in line with those already
described previously for both wind turbine blades and towers.
[0251] In a further embodiment of the wind turbine concrete tower
the height is above 80 meters.
[0252] One effect of this embodiment is that for towers higher than
80 meters, concrete towers may be the most economical feasible
solution compared to steel towers.
[0253] In general, concrete towers containing functionalized
graphene-containing material may offer a welcome opportunity to
increase the height of wind turbine towers. This may also lead to
wind turbines with an increased size in rotors. It may further
offer the possibility of raising rotors to a height where a better
wind regime may be reach with the opportunity to capture more
and/or stronger wind, and therefore increase the efficiency of the
wind turbines and at the same time reduce the service costs over
lifetime. A better wind regime may also include more continuous
wind with reduced risk of turbulence and gusts arising.
[0254] A wind turbine tower with a height above 80 may have these
above mentioned effects and advantages as a larger hub height of
the rotor may achieve less turbulence in the wind turbine, stronger
winds and more energy production--each meter gained in hub height
is said to increases the yearly energy yield by 0.5-1%.
[0255] Generally tower heights both onshore and offshore are
increasing based on this reason of achieving better wind regimes.
Currently, tower heights now up to 150 meters are appearing.
Onshore sites are moving more inland which means that the
surroundings may have a significant influence on the wind regime.
This may include forestry areas and/or hilly terrain. Thus one
effect of increasing the tower height to above 80 meters may be to
achieve better wind regimes onshore unheeded the surroundings with
the mentioned advantages hereof.
[0256] In one embodiment of the wind turbine concrete tower, the
surface may comprise a multi-layered structure configured with at
least one functional layer containing functionalized
graphene-containing material. The multi-layered structure may
provide a functional surface area.
[0257] One effect of the embodiment may be that the layered
structure may provide a surface functionality not present in the
top layer in itself. The surface functionality may be caused from
another layer in the structure. This may have the advantage of
obtaining a top layer acting for example as a protective layer for
another layer in the layered structure.
[0258] In one aspect the top layer may be the functional layer
containing functionalized graphene-containing material,
[0259] In another aspect a functional layer containing
functionalized graphene-containing material, may be a different
layer that the top layer.
[0260] In one aspect the multi-layered structure may be a sandwich
structure comprising multiple functional layers, with at least one
functional layer having a functionality being different from the
functionality of another functional layer.
[0261] One effect of this embodiment may be that a multifunctional
surface may be achieved. Such a multifunctional surface may be
impossible to achieve using a single functional layer, because the
graphene structures giving the different layer functionalities may
not be compatible together in the same matrix material.
[0262] Multiple layer functionalities may per nature of the layer
functionality not be incorporated in one layer. One exemplary
embodiment could be a functional layer being stretchable and
another layer having high mechanical stability which could be
relevant for use on a substrate with a high thermal expansion
coefficient.
[0263] Another effect may be that one of the layer functionalities
are enhanced by incorporating an additional functional layer with
different layer functionality. One exemplary embodiment could be a
functional top layer with a high wearability or high environmental
resistance in combination with a functional intermediate layer
which is resilient or shock-absorbing. This combination may result
in an enhanced wearability or environmental resistance of the outer
surface due to decreasing the influence of impacting forces on the
outer surface.
[0264] In general, the effects and advantages of a multi-layered
structure comprised in the surface of the wind turbine concrete
tower may be in line with those previously described for the wind
turbine blade, comprising a multi-layered structure comprising a
functionalized graphene-containing material as part of the
surface.
[0265] An object of the invention may be achieved by use of
functionalized graphene-containing material in a wind turbine
concrete tower extending vertically to a height.
[0266] A further object of the invention may be achieved by use of
functionalized graphene-containing material in a surface coating of
a wind turbine tower extending vertically to a height.
[0267] In one aspect functionalized graphene-based material may be
mixed into a matrix of intermediary or host/carrier materials.
[0268] In one aspect the functionalized graphene-based material may
be in dry powder form,
[0269] In one aspect the functionalized graphene-based material may
be in liquid form.
[0270] In one aspect the functionalized graphene-based material may
be an ink.
[0271] The effects and advantages of the use of functionalized
graphene-containing material in the wind turbine concrete tower
structure or in a surface coating of a wind turbine tower may be in
line with those previously described for a wind turbine tower
comprising a load carrying concrete structure extending vertically
to a height, comprising a functionalized graphene-containing
material.
[0272] Item: A wind turbine foundation comprising a load carrying
concrete structure comprising functionalized graphene-containing
material anchoring the concrete tower to the ground
[0273] One effect may be the use of functionalized
graphene-containing material in foundations may offer an
opportunity to reduce the amount and/or weight of steel
reinforcement
[0274] A further effect may be increased terminal conductivity,
which may be advantageous in a manufacturing process due to: [0275]
faster hardening time due to faster temperature equilibrium, [0276]
increased resistance to delamination during fabrication, [0277]
reduced exothermic and micro cracking during fabrication, [0278]
enabling thicker section mouldings and manufacture of thicker
structures, [0279] more homogeneous and better part quality, [0280]
reduced process costs, amongst others.
[0281] Further effect and advantages of the embodiment of this item
may be in line with those described in relation to the embodiment
of a wind turbine concrete tower comprising a load carrying
concrete structure extending vertically to a height, comprising
functionalized graphene-containing material concerning the material
properties i.e. where the function of the units are comparable.
[0282] An object of the invention may be achieved by use of
functionalized graphene-containing material in a repair system for
wind turbine tower foundations.
[0283] A wind turbine may comprise a load carrying concrete
structure and an imbedded steel reinforcement and a foundation
where the foundation is connected to the bottom of the tower.
[0284] This embodiment may include repairing units where steel
towers connected to a steel cylinder or foundation ring imbedded in
the concrete foundation is dislocated or moves more than an
acceptable distance relative to the concrete foundation
[0285] The advantages of such a repair system may be a system with
additional strength, additional flexibility and/or more suitable
viscosity in use e.g. during application. The use of functionalized
graphene-containing material in such a repair system may also
provide for better electrical conductivity. This may be
advantageous in regard to achieving a low energy consuming heating
system, where the passage of an electric current through a
conductor produces heat, also known as Joule heating, Ohmic heating
or resistive heating. This may be advantageous in regard to
achieving optimized fit and bonding of a suitable liquid repair
system using a functionalized graphene-containing material with a
suitable viscosity when followed by a heat driven hardening process
as part of the repair process, and thus improved final performance
of the repair system.
[0286] Item: Use of functionalized graphene-containing material in
material mix for nacelle covers and/or spinner.
[0287] Effects and advantages of this embodiment may be in line
with the previously described advantages for wind turbine blades
and wind turbine concrete towers comprising functionalized
graphene-containing material where the functions of the units are
comparable.
[0288] Items: [0289] Lightning and electro-static conductor system
for existing and new wind turbines, in the blades (load-carrying
web and/or the shell structure and/or the surface coatings), in the
tower (load carrying concrete structure and/or the surface) and in
the foundation (load carrying concrete structure and/or the
surface) where at least one of these comprising a functionalized
graphene-containing material, providing an conducive material.
[0290] De-icing system for existing and new wind turbines, in the
blades (load-carrying web and/or the shell structure and/or the
conductive surface coatings), in the tower (load carrying concrete
structure and/or the surface) and in the foundation (load carrying
concrete structure and/or the surface) where at least one of these
comprising a functionalized graphene-containing material, providing
an electrical conducive material where the passage of an electric
current through this conductor produces heat, also known as Joule
heating, Ohmic heating and resistive heating. [0291] Surface
coating/liquid/ink/etc. for existing and new wind turbines which
comprises a functionalized graphene-containing material providing
improved barrier properties of the surface such as a hydrophobic,
wear resistant and environmental resistant surface providing
completely new properties to all surface areas of wind turbines.
[0292] Increased strength, stiffness and toughness of the blade
structure enabling longer, stiffer, lighter, more damage-tolerant,
less service and maintenance demanding and more aerodynamic
efficient blades when load-carrying web and/or the shell structure
and/or the surface coatings comprising a functionalized
graphene-containing material [0293] Increased strength, stiffness
and toughness of the tower structure enabling longer, stiffer,
lighter, more damage-tolerant, less service and maintenance
demanding and longer lifetime for towers when load carrying
concrete structure and/or the surface comprising a functionalized
graphene-containing material [0294] Wind turbine concrete tower
assembly systems and methods which compared to traditional concrete
towers may: [0295] reduce the amount of concrete and the amount of
steel reinforcement required and thereby allow adoption of thinner
and lighter concrete towers, allowing for new designs, reduced
concrete consumption and improved environmental sustainability.
[0296] enable a completely new logistical puzzle of not being too
heavy or wide to cross all the roads and bridges from production
facility to the wind turbine site which again may reduce logistic
costs considerably. [0297] enable new concrete tower assembly
systems and methods which may reduce the need for large cranes on
site which again will reduce costs. [0298] enable new concrete
tower assembly systems and methods which may offer considerably
more strength in the towers themselves and therefore also the
opportunity to use new inventions of cranes "crawling" up and down
on the tower structure when erecting and servicing the wind
turbines which again will reduce costs and will also offer a
welcome opportunity to introduce towers which is even higher than
today. [0299] Wind turbine concrete towers containing
functionalized graphene-containing material may offer a welcome
opportunity to make towers even higher to support bigger rotors and
to get rotors up in a better wind regime and therefore capture more
wind and therefore increase the efficiency of the wind turbines and
at the same time reduce the service costs over lifetime.
[0300] In further embodiments the functionalized
graphene-containing material may be comprised in any combination of
two or more of the described parts of the wind turbine (blade,
tower, rotor, foundation repair system) and/or in combination with
the graphene-containing sensor.
[0301] Combining parts comprising functionalized
graphene-containing material may have the effect that the weight of
single parts of the wind turbine may be reduce while maintaining or
improving properties for the entire wind turbine such as strength,
stiffness, toughness, flexibility and/or functionalized surfaces
compared to a wind turbine tower using non-graphene-containing
material parts. This may be advantages in regard to that a reduced
deflection/bending of the parts and/or the entire wind turbine may
be achieve for reduced fatigue and thus prolonged lifetime. Further
advantages may be mitigating the risk of cracks in the parts and/or
the entire wind turbine in general achieving more damage-tolerant
wind turbines. Mitigating the risk of damages or increasing the
damage-tolerance may generally result in reduced service costs and
extend lifetime.
[0302] In general, this may achieve for new designs of the wind
turbines, as the change in some parts of the wind turbine may
affect changes in other parts of the wind turbine for achieving the
aimed properties of the entire wind turbine.
[0303] The further combination with the graphene-containing sensor
may have an effect of a change in which mechanical properties to
survey and/or how to measure such properties. This may further
achieve for new designs of control systems used in wind
turbines.
[0304] In further embodiments the use of functionalized
graphene-containing material may be combined by using it in any
combination of two or more of a blade structure, a wind turbine
concrete tower, a surface coating of a wind turbine tower and/or
repair system for wind turbine tower foundation.
[0305] The use of multiple functionalized graphene-containing
material parts in a wind turbine may have the previously described
effects achieved using a combination of multiple parts comprising
functionalized graphene-containing material, but in this case for
the entire wind turbine or dedicated areas of the wind turbine. In
general, this may further achieve for new designs of the wind
turbines, as the change in some parts of the wind turbine may
affect changes in other parts of the wind turbine for achieving the
aimed properties of the wind turbine. It may further achieve for
new designs and implementation of how and/or where the wind turbine
installation may be installed.
[0306] In general, by combining the apparatuses and use the effects
described for the individual parts or use may be enhanced for a
combination of parts.
DESCRIPTION OF THE DRAWING
[0307] FIG. 1: Illustration of a wind turbine.
[0308] FIG. 2: Illustration of a wind turbine blade.
[0309] FIG. 3: Illustration of two embodiments of a multi-layered
structure.
[0310] FIG. 4: Illustration of a typical foundation for a steel
tower for a wind turbine.
[0311] FIG. 5: Illustrating the road map to functionalized
graphene-containing material
DETAILED DESCRIPTION OF THE INVENTION
TABLE-US-00001 [0312] No Item 10 Wind turbine blade 12 Blade
structure 14 Wind turbine 20 Shell structure 21 Multi-layered
structure 22 Sandwich structure 23 Top layer 24 Intermediate layers
25 Bottom layer 26 Dedicated blade area 27 Functional surface area
28 Surface area 29 Layer thickness 30 Load-carrying spar 40
Functionalized graphene-containing material 41 Tape (film) 42
Graphene-based material 44 Functionalized graphene-based material
46 Host/carrier material 47 Functional layer 48 Functionality 49
Resilient layer 50 Blade root 55 Hub 60 Conductive structure 70
Surface 72 Hydrophobic surface 73 Conductive surface 74 Wear
resistant surface 75 Light absorbing surface 76 Surface coating 77
Radar-absorbent surface 80 Wind turbine concrete tower 81 Wind
turbine tower 82 Load carrying structure 83 Transition piece 84
Height 85 Nacelle 86 Repair system 88 Tower foundation 90 Sensor
containing graphene 91 Rotor 92 Leading edge 93 Tailing edge 94
Suction side 95 Pressure side 100 Use 200 Method 210 Retrofitting
301 Hub height 302 Blade length 310 Soil 312 Mounting element 314
Foundation top flange 400 Method for functionalization
[0313] FIG. 1 illustrates a wind turbine 14 comprising a rotor 91,
a nacelle, a tower 80 and foundation 88 for the wind turbine 14.
The rotor 91 may comprise the wind turbine blades 10 comprising a
blade structure 12, blade roots 50 and a hub 55. The nacelle 85 is
illustrated with a cover. The illustrated embodiment comprises a
wind turbine concrete tower 80 with a load-carrying structure 82.
The load-carrying structure 82 constitutes a top part zone, a
middle section zone and a base section zone. The middle section
zone and the base section zone may be precast pre-stressed concrete
shells. Alternatively the base section zone may be cast in situ.
The top part of the tower is illustrated to comprise two sections
which may comprise mainly steel elements. The upper section zone
includes a transition piece 83. The transition piece 83 may be made
in steel with flanges connecting to a yaw system and/or a nacelle
85. The upper section zone may comprise steel tubes or
alternatively precast pre-stressed concrete shells.
[0314] The illustrated embodiment presents a hybrid concrete tower,
which is referred to as a concrete tower 80 in this invention. The
tower has a height 84 and the hub height 301 is illustrated along
with the blade length 302. The hub height 301 differs from the
tower height 84 by an additional height given by the hub 55.
[0315] FIGS. 2A, 2B and 2C illustrate a wind turbine blade 10. The
wind turbine blade 10 comprises a blade structure 12 with a leading
edge 92, a tailing edge 93, a suction side 94 and a pressure side
95. The leading edge 92 is that edge of a wind turbine blade 10
that cuts through the air. It is generally that region of the blade
10 which experiences the highest level of erosion.
[0316] The illustrated wind turbine blade 10 comprises a shell
structure 20 and a load carrying spar 30. The wind turbine blade
further comprises a surface 70.
[0317] In FIG. 2A the load carrying spar 30 is illustrated as a
load carrying box. It may also be referred to as a load-carrying
box, a main spar, a spar web, a load carrying web, amongst
others.
[0318] In FIG. 2B the load carrying spar 30 is illustrated as a
single load carrying structure. It may also be referred to as a
main spar, a spar web, a load carrying web, amongst others. The
blade structure may comprise a hydrophobic surface 72, a conductive
surface 73, a wear resistant surface 74, a light absorbing surface
75 and/or a radar-absorbent surface 77. The blade structure may
comprise a surface coating 76 which may constitute the surface
70.
[0319] In FIG. 2C the leading edge 92 of a wind turbine blade 10 is
illustrated. The leading edge is part of the surface 70. The
leading edge 92 is illustrated as two different areas. The extent
of the leading edge may depend on the design of the blade and the
specifications of the blade. The leading edge 92 may only refer to
the outer-most tip part illustrated by the black area or it may
extend more towards the rod of the blade illustrated by the black
and white area.
[0320] FIG. 3A illustrates a layered structure 21 being a sandwich
structure 22 with six layers 12. The layered structure 21 comprises
a bottom layer 25, four intermediate layers 24 and a top layer 23.
The layers each have individual film thicknesses 29.
[0321] In the illustrated embodiment, the top layer 23 and the
intermediate layers 24 all have different functionalities and may
accommodate a surface being super environmentally resistant. The
top layer 23 provides for a hydrophobic 72 and wear resistant 74
surface. The intermediate layer 24 is a resilient layer 49. This
layer's properties of being flexible and/or impact-absorbing may,
in combination with the wear resistant top layer, add a further
contribution to the wear resistance 74 of the functional surface
and thus being super environmentally resistant. This may be due to
dampening the impacts of particles inflicting on the surface area.
The intermediate layer 24 adjacent to the resilient layer 49 may
accommodate a functional layer 47 being light-absorbing 75 and
thus, with a reduced light reflectance back to the top layer 23.
The intermediate layer 24, adjacent to the light-absorbing layer
75, may be a conductive 73 functional layer 47 accommodating for
Joule heating to support a de-icing functionality. The next
intermediate layer 24, being the layer between the conductive
functional layer 73 and the bottom layer 25 may accommodate an
organic solar cell or a photovoltaic. This layer may provide a
functionality 48 of delivering power to the Joule heating and thus
the de-icing functionality.
[0322] FIG. 3B illustrates a layered structure 21 being a sandwich
structure 22 with four layers 12. The layered structure 21
comprises a bottom layer 25, two intermediate layers 24 and a top
layer 23.
[0323] In the illustrated embodiment, the top layer 23 and the
intermediate layers 24 all have different functionalities and may
accommodate a surface being super environmentally resistant. The
top layer 23 provides for a hydrophobic 72 and wear resistant 74
surface.
[0324] The intermediate layer 24 adjacent to the top layer 23 is a
functional layer 47 being radar absorbent and thus, accommodates
for a radar absorbent surface 77. The intermediate layer 24
adjacent to the radar-absorbent layer 77 is also a functional
layer. This layer could be absorbent for other wavelengths, be
stretchable, add strength to the structure, provide conductive
structures amongst others.
[0325] FIG. 4 illustrates an embodiment of a tower foundation. The
foundation is typically arranged in the soil 310 for on shore wind
turbines. A typical foundation 88 for a steel tower for a wind
turbine may comprise a mounting element 312 comprising T- and
L-flanges and an embedded ring, where the L-flange may be
connecting to the steel tower and may constitute the foundation top
flange 314.
[0326] FIG. 5 illustrates the roadmap to reach functionalized
graphene-containing material 40. Graphene-based material 42 is
functionalized using a method or process for functionalization 400
resulting in a functionalized graphene-based material 44. The
functionalized graphene-based material 44 is/are mixed with
host/carrier material 46 resulting in functionalized
graphene-containing material 40.
* * * * *